ant-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Al Le" <Al...@gmx.de>
Subject Aw: Re: How to override a property that was set in the command line via "-D..."
Date Thu, 31 Jul 2014 13:53:48 GMT
Hello Peter.

Thank you for the advice! This should work indeed! I have not tried yet,
but from reading the code I'm quite sure it will. It's a bit less nice
(there are two properties instead of just one), but it will work.

Though I'm still not quite satisfied that a script works differently depending
on how its properties have been set by the caller. IMO the result of a script
should not depend on that.

It's like if a Java function taking an int parameter would work differently
depending on whether you passed it as "5" or "3+2".

Why are there so called user properties at all?

Thank you once again for the proposal.

Al






> Gesendet: Donnerstag, 31. Juli 2014 um 15:06 Uhr
> Von: "Peter West" <lists@pbw.id.au>
> An: "Ant Users List" <user@ant.apache.org>
> Betreff: Re: How to override a property that was set in the command line via "-D..."
>
> Peter West
> 
> "...the kingdom of heaven is like a merchant in search of fine pearls, who, finding one
pearl of great value, sold all that he had and bought it."
> 
> Just define "well-known" properties which can be used from the command line, or set from
within a master file, and define another "actual" property which will take precedence.  Add
logic to called.xml and siblings to assign the "public" value to the "actual" outfile variable.
 If the actual variable was set at a higher level, that setting will take precedence. Otherwise,
the value from the "public" well-known property will become the value of the "actual" variable.
> 
> Just make sure to document it within the file, so that someone trying to work out why
the command line option didn't "take" will be able to find it.
> 
> <project name="Main" default="run">
> 	
>    <target name="run">
>         <property name="outFileName" value="START"/>
>    	<echo>Main: outFileName: ${outFileName}</echo>
>    	
>    	<ant antfile="called.xml" target="run">
>    	    <property name="realFileName" value="OTHER VALUE"/>
>    	</ant>
>    </target>
> 	
> </project>
> 
> <project name="called" default="run">
> 
>    <property name="realFileName" value="${outFileName}"/>
> 	
>    <target name="run">
>    	<echo>called: outFileName: ${realFileName}</echo>
>    </target>
> 	
> </project>
> 
> Peter West
> 
> "...the kingdom of heaven is like a merchant in search of fine pearls, who, finding one
pearl of great value, sold all that he had and bought it."
> 
> 
> On 31 Jul 2014, at 10:02 pm, Al Le <Al.Le@gmx.de> wrote:
> 
> > Hello.
> > 
> > Thank you for the quick reply.
> > 
> > I know that properties are immutable and should not be redefined. But my situation
is,
> > that the caller (be it command line or an ant script) sets the property for the
called
> > script.
> > 
> > If the property is defined not in the command line but in the script itself (using
the
> > 'property' task) then the property is substituted in the called script. Bit if it's
set
> > from the commnd line, it's not.
> > 
> > I looked into the ant source code. The reason seems to be that the properties that
are
> > defined in the command line are set as *user* properties. Those properties can't
be
> > redefined even through direct calls to project.setProperty().
> > 
> > How would you implement my goal (I hope it's clear what it is)?
> > 
> > If the main script is like this:
> > 
> > <project name="Main" default="run">
> > 	
> >    <target name="run">
> >         <property name="outFileName" value="START"/>
> >    	<echo>Main: outFileName: ${outFileName}</echo>
> >    	
> >    	<ant antfile="called.xml" target="run">
> >    	    <property name="outFileName" value="OTHER VALUE"/>
> >    	</ant>
> >    </target>
> > 	
> > </project>
> > 
> > and I call it as "ant -f main.xml" (no "-D...") then the called script gets the
value
> > "OTHER VALUE".
> > 
> > So why do the properties set from the command line get set as user properties whereas
> > properties set by the "property" task are set as usual properties?
> > 
> > I think they should be set in the same way.
> > 
> > Cheers
> > Al
> > 
> > 
> > 
> >> Gesendet: Donnerstag, 31. Juli 2014 um 12:15 Uhr
> >> Von: "Knuplesch, Jürgen" <Juergen.Knuplesch@icongmbh.de>
> >> An: "Ant Users List" <user@ant.apache.org>
> >> Betreff: AW: How to override a property that was set in the command line via
"-D..."
> >> 
> >> Hello,
> >> 
> >> because of the immutability of properties you have to redesign your scripts.
> >> The first time you set a property is it. You are usually not able t change it
later.
> >> This is very important, because this is the only way to set properties from
outside.
> >> 
> >> Why does your command line call then use "-D-DoutFileName=START", when you don’t
want it?
> >> 
> >> Never do this, when you want to change the prop in your build.
> >> If "START" is your default, then set it in the called target / Ant file, in
your case "called.xml"
> >> 
> >> Its very important to understand why immutability is a feature and not a bug...
(-;
> >> 
> >> Juergen
> >> 
> >> 
> >> 
> >> 
> >> 
> >> -----Ursprüngliche Nachricht-----
> >> Von: Al Le [mailto:Al.Le@gmx.de] 
> >> Gesendet: Donnerstag, 31. Juli 2014 11:10
> >> An: user@ant.apache.org
> >> Betreff: How to override a property that was set in the command line via "-D..."
> >> 
> >> user@ant.apache.org
> >> 
> >> How to override a property that was set in the command line via "-D..."
> >> 
> >> Hello.
> >> 
> >> Could someone please help me with the following situation?
> >> 
> >> I have some ant scripts that are used in two ways:
> >> 
> >> 1. Standalone build, i.e. the script is executed directly from the command line
2. As a part of a larger build -- then the script is called via 'ant' from another
> >>    script (here we have a main and a called scripts).
> >> 
> >> Each script uses a property 'outFileName' that specifies where to write some
output to.
> >> Both the main and the called script use this property. The script gets the value
of the property passed from the caller.
> >> 
> >> The root script (i.e. the one called from the command line) gets passed the
value of 'outFileName' via the "-DoutFileName=..." option.
> >> 
> >> When the main script calls a called script, it may specify another value for
the property 'outFileName' (using the nested 'property' element). The called script should
notice no difference how it was called (i.e. whether it is called from the command line or
as a called script from another script).
> >> 
> >> Now the propblem: It turns out that the properties specified via "-D=..." are
set as *user* properties. Hence it's not possible to redefine them via the nested elements.
Ant not even using a script task with a call 'project.setProperty()'.
> >> 
> >> How would you solve this situation? I would not like introduce properties with
a different name, since my goal is to have scripts that can be 'customized' by specifying
a property with a well known name ('outFileName') -- be it on the command line or trough a
nested element of an ant task. Thik of it as of script interface.
> >> 
> >> The only possible solution I can think of is to specify a custom property helper,
but that's too much IMO and makes scripts not 'portable'.
> >> 
> >> Here's an example that I hope would explain the problem (I use ant 1.8.4 but
I think the same problem would also occur with ant 1.9.x):
> >> 
> >> 
> >> -- Main build file 'main.xml' --
> >> 
> >> <project name="Main" default="run">
> >> 	
> >>    <target name="run">
> >>    	<echo>Main: outFileName: ${outFileName}</echo>
> >>    	
> >>    	<ant antfile="called.xml" target="run">
> >>    		<property name="outFileName" value="OTHER VALUE"/>
> >>    	</ant>
> >>    </target>
> >> 	
> >> </project>
> >> 
> >> 
> >> -- Called build file 'called.xml' --
> >> <project name="Called" default="run">
> >> 	
> >>    <target name="run">
> >>    	<echo>Called: outFileName: ${outFileName}</echo>
> >>    </target>
> >> 
> >> </project>
> >> 
> >> 
> >> -- Command line --
> >> ant -f main.xml -DoutFileName=START
> >> 
> >> 
> >> -- Actual output --
> >> run:
> >>     [echo] Main: outFileName: START
> >> run:
> >>     [echo] Called: outFileName: START
> >> 
> >> 
> >> -- Expected (desired) output --
> >> run:
> >>     [echo] Main: outFileName: START
> >> run:
> >>     [echo] Called: outFileName: OTHER VALUE
> >> 
> >> 
> >> Any help will be much appreciated.
> >> 
> >> Al
> >> 
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: user-unsubscribe@ant.apache.org For additional commands,
e-mail: user-help@ant.apache.org
> >> 
> >> 
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: user-unsubscribe@ant.apache.org
> >> For additional commands, e-mail: user-help@ant.apache.org
> >> 
> > 
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: user-unsubscribe@ant.apache.org
> > For additional commands, e-mail: user-help@ant.apache.org
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@ant.apache.org
> For additional commands, e-mail: user-help@ant.apache.org
> 
>

---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@ant.apache.org
For additional commands, e-mail: user-help@ant.apache.org


Mime
View raw message